Selective Push-to-Talk

ABSTRACT

A push-to-talk (PTT) switch with biasing to a first center position in which in which the PTT function of neither one of up to two audio devices is engaged, also having a first operated position to which the switch may be moved by hand operation to cause the PTT function of the first one of the two audio devices to be engaged, and further having a second operated position to which the switch may be moved by hand operation to cause the PTT function of the second one of the two audio devices to be engaged.

TECHNICAL FIELD

This disclosure relates to monitoring connection between a headset andone or more of an intercom system (ICS) and a radio, and toautomatically altering the operation of a passive audio mixer and/or apush-to-talk (PTT) manually-operable control.

BACKGROUND

Two-way communications headsets are in common use in many types ofvehicles and with various large pieces of machinery, especially vehiclesand machinery that create or are typically operated in a high noiseenvironment such that necessary two-way communications with the driver,operator or pilot would be impaired without such headsets. Examples ofsuch noisy environments include airplane cockpits, driver's compartmentsin commercial trucks and tractors, operator cabins in cranes and tunnelboring machines, and crew compartments in tanks and other militaryvehicles. It is commonplace for such vehicles and machinery toincorporate an intercom system providing one or more connection pointsto which such headsets are coupled. Such intercoms typically cooperatewith multiple ones of such headsets to enable personnel within or in theimmediate vicinity of such vehicles to communicate with each other, andsuch intercoms typically incorporate long-range wireless transceiversenabling personnel to use such headsets in communicating with otherpersonnel at a distance.

It has recently become desired to further enable such headsets to becoupled to portable audio devices that personnel may carry with them, inaddition to being able to be coupled to an intercom system of a vehicleor large piece of machinery. Therefore, it has become desirable toenable the simultaneous coupling of a headset to both an intercom systemand a personal audio device in a manner that provides a high degree ofease of use of such a combination, and incorporates the ability tomaintain a high degree of functionality in the event of the headsetlosing power normally provided by its own power source without drainingthe power sources of portable radios or other devices to which theheadset is connected.

SUMMARY

A push-to-talk (PTT) switch with biasing to a first center position inwhich in which the PTT function of neither one of up to two audiodevices is engaged, also having a first operated position to which theswitch may be moved by hand operation to cause the PTT function of thefirst one of the two audio devices to be engaged, and further having asecond operated position to which the switch may be moved by handoperation to cause the PTT function of the second one of the two audiodevices to be engaged. Apparatus and method to monitor the coupling ofone or two audio devices and to augment the function of the PTT switchto cause the PTT function of one audio device to be engaged regardlessof which of the two operated positions into which the switch is moved inresponse to there being only the one audio device coupled to theapparatus and in response to the one audio device being a radio, tocause the PTT function of either one of two audio devices to be selectedto be engaged depending on which operated position to which the PTTswitch is moved in response to there being only one audio device in theform of an intercom system (ICS) coupled to the apparatus with the otheraudio device in the form of a radio being coupled through the ICS, andto allow the PTT to be used to select the PTT function of either one oftwo audio devices to be engaged in response to there being two audiodevices in the form of radios coupled to the apparatus. Apparatus andmethod to mix audio provided by a radio with audio provided by an ICS inwhich the audio of the radio being mixed with audio provided by the ICSand presented to one ear of a user, and in which audio provided by theICS is presented to the other ear of the user without being mixed withaudio provided by the radio.

In one aspect, an apparatus includes a first connector to enable thecoupling of a first audio device to the apparatus; a second connector toenable the coupling of a second audio device to the apparatus; and apush-to-talk (PTT) switch having a center position, operable to a firstnon-center position from the center position to engage a PTT function ofthe first audio device at a time when the first audio device is coupledto the apparatus, operable to a second non-center position from thecenter position to engage a PTT function of the second audio device at atime when the second audio device is coupled to the apparatus,mechanically structured to prevent the PTT functions of both of thefirst and second audio devices from being simultaneously engaged, and inwhich a biasing force tends to bias the PTT switch towards the centerposition from the first and second non-center positions.

Implementations may include, and are not limited to, one or more of thefollowing features. The PTT switch may include a rocker switch having afirst surface and a second surface, wherein the PTT switch is operableto the first non-center position by pressing on the first surface and isoperable to the second non-center position by pressing on the secondsurface. The PTT switch may further include a spring providing at leasta portion of the biasing force to tend to bias the PTT switch toward thecenter position from at least one of the first and second non-centerpositions. The apparatus may further include a communications microphoneto detect speech to be conveyed to at a remotely located person throughthe PTT function of one of the first and second audio devices of whichthe PTT function is engaged through operation of the PTT switch.

The apparatus may include a headset having at least one acoustic driverstructured to be positioned adjacent at least one ear of a user of theapparatus at a time when the apparatus is worn on the user's head toacoustically output audio provided by at least one of the first andsecond audio devices. The PTT switch may be disposed on a casing of theheadset in which the acoustic driver is disposed. The apparatus mayfurther include a control box on which the PTT switch is disposed andcoupled to a casing of the headset in which the acoustic driver isdisposed by a cable or by a wireless connection.

In another aspect, an apparatus includes a first radio; a second radio;and a push-to-talk (PTT) switch having a center position, operable to afirst non-center position from the center position to engage a PTTfunction of the first radio, operable to a second non-center positionfrom the center position to engage a PTT function of the second radio,mechanically structured to prevent the PTT functions of both of thefirst and second radios from being simultaneously engaged, and in whicha biasing force tends to bias the PTT switch towards the center positionfrom the first and second non-center positions.

Implementations may include, and are not limited to, one or more of thefollowing features. The PTT switch may include a rocker switch having afirst surface and a second surface, wherein the PTT switch is operableto the first non-center position by pressing on the first surface and isoperable to the second non-center position by pressing on the secondsurface. The PTT switch may further include a spring providing at leasta portion of the biasing force to tend to bias the PTT switch toward thecenter position from at least one of the first and second non-centerpositions. The apparatus may further include a communications microphoneto detect speech to be conveyed to at a remotely located person throughthe PTT function of one of the first and second radios of which the PTTfunction is engaged through operation of the PTT switch.

The apparatus may include a headset having at least one acoustic driverstructured to be positioned adjacent at least one ear of a user of theapparatus at a time when the apparatus is worn on the user's head toacoustically output audio provided by at least one of the first andsecond radios. The PTT switch may be disposed on a casing of the headsetin which the acoustic driver is disposed.

In still another aspect, an apparatus includes a radio; an intercomsystem (ICS); and a push-to-talk (PTT) switch having a center position,operable to a first non-center position from the center position toengage a PTT function of the radio, operable to a second non-centerposition from the center position to engage a PTT function of the ICS,mechanically structured to prevent the PTT functions of both of theradio and the ICS from being simultaneously engaged, and in which abiasing force tends to bias the PTT switch towards the center positionfrom the first and second non-center positions.

Implementations may include, and are not limited to, one or more of thefollowing features. The PTT switch may include a rocker switch having afirst surface and a second surface, wherein the PTT switch is operableto the first non-center position by pressing on the first surface and isoperable to the second non-center position by pressing on the secondsurface. The PTT switch may further include a spring providing at leasta portion of the biasing force to tend to bias the PTT switch toward thecenter position from at least one of the first and second non-centerpositions. The apparatus may further include a communications microphoneto detect speech to be conveyed to at a remotely located person throughthe PTT function of one of the radio and the ICS of which the PTTfunction is engaged through operation of the PTT switch.

The apparatus may include a headset having at least one acoustic driverstructured to be positioned adjacent at least one ear of a user of theapparatus at a time when the apparatus is worn on the user's head toacoustically output audio provided by at least one of the radio and theICS. The PTT switch may be disposed on a casing of the headset in whichthe acoustic driver is disposed.

Other features and advantages of the invention will be apparent from thedescription and claims that follow.

DESCRIPTION OF THE DRAWINGS

FIGS. 1 a and 1 b are perspective diagrams of variants of a headset.

FIGS. 2 a and 2 b are perspective diagrams providing a closer view ofvariants of a controller portion of the headset of FIG. 1 a.

FIG. 3 is a block diagram of an electrical architecture employable in aportion of either variant of the headset of FIG. 1 a or 1 b.

FIGS. 4 a through 4 e are each a portion of the block diagram of FIG. 3,with each additionally depicting the attachment of different ones andcombinations of the cables of either variant of the headset of FIG. 1 aor 1 b, along with different ones and combinations of audio devicesthrough those cables.

FIGS. 5 a and 5 b are block diagrams of alternate architecturesproviding a subset of the function of the architecture of FIG. 3.

FIGS. 6 a and 6 b are perspective diagrams of alternate devicesproviding a subset of the function of either variant of the headset ofFIG. 1 a or 1 b.

DETAILED DESCRIPTION

What is disclosed and what is claimed herein is intended to beapplicable to a wide variety of headsets, i.e., devices structured to beworn on or about a user's head in a manner in which at least oneacoustic driver is positioned in the vicinity of an ear, and in which atleast one microphone is positioned in the vicinity of the user's mouthto enable two-way audio communications. It should be noted that althoughspecific embodiments of headsets incorporating a pair of acousticdrivers (one for each of a user's ears) are presented with some degreeof detail, such presentations of specific embodiments are intended tofacilitate understanding through examples, and should not be taken aslimiting either the scope of disclosure or the scope of claim coverage.

It is intended that what is disclosed and what is claimed herein isapplicable to headsets that also provide active noise reduction (ANR),passive noise reduction (PNR), or a combination of both. It is intendedthat what is disclosed and what is claimed herein is applicable toheadsets structured to be connected with at least an intercom systemand/or at least one radio through a wired connection, but which may befurther structured to be connected to any number of additional devicesthrough wired and/or wireless connections. It is intended that what isdisclosed and what is claimed herein is applicable to headsets havingphysical configurations structured to be worn in the vicinity of eitherone or both ears of a user, including and not limited to, over-the-headheadsets with either one or two earpieces, behind-the-neck headsets,two-piece headsets incorporating at least one earpiece and a physicallyseparate microphone worn on or about the neck, as well as hats orhelmets incorporating one or more earpieces and one or more microphonesto enable audio communication. Still other embodiments of headsets towhich what is disclosed and what is claimed herein is applicable will beapparent to those skilled in the art.

FIG. 1 a depicts an embodiment of a headset 1000 having an“over-the-head” physical configuration. The headset 1000 incorporates ahead assembly 100, a control box 200, and one or more of cables 300 a,300 b and/or 300 c. The head assembly 100 incorporates a pair ofearpieces 110 a and 110 b that each incorporate an acoustic driver 115 aand 115 b, respectively, a headband 120 that couples together theearpieces 110 a and 110 b, a microphone boom 130 extending from theearpiece 110 b to support a communications microphone 135, and a cable140 coupling the earpiece 110 b to the control box 200. The control box200 incorporates a casing 210, a manually-operable push-to-talk (PTT)switch 215, and a pair of connectors 220 a and 220 b by which one ormore of the cables 300 a-c may be coupled to the control box 200. Eachof the cables 300 a-c are configured to enable one or more audio devicesto be coupled to the control box 200, specifically, one or more of aradio 700, a vehicle intercom system (ICS) 800 (and perhaps to a vehicleradio 850 through the ICS 800), a radio 900 and an audio source 950.

It should be noted that although the head assembly 100 is depicted withboth the cable 140 and the microphone boom 130 being coupled to the sameone of the earpieces 110 a and 110 b, other configurations of the headassembly 100 are possible in which they are coupled to separate ones ofthe earpieces 110 a and 110 b. It should be noted that although thecable 140 is depicted in a manner suggesting that the cable 140 iscoupled to both the earpiece 110 b and the control box 200 withoutconnectors such that the cable 140 is not separable from either ofthese, other configurations are possible in which connectors (not shown)are used to couple the cable 140 to one or both of these. It should benoted that although the control box 200 is depicted as having aparticular shape and a particular size relative to other components ofthe headset 1000, the control box 200 may be of any of a variety ofsizes and shapes. Further, although the control box 200 is depicted asbeing physically distinct from all components of the head assembly 100,other configurations of the headset 1000 are possible in which thecontrol box 200 is integrated into one of the earpieces 110 a or 110 b(such that the PTT switch 215 may be disposed on a casing of one or theother of the earpieces 110 or 110 b, for example), or is integrated intothe head assembly 100 in some other manner. It should be noted thatalthough the connectors 220 a and 220 b are depicted as being disposedon the casing 210 of the control box 200, other configurations arepossible in which one or both of the connectors 220 a and 220 b areseparated from the casing 210 and are coupled to the casing 210 via oneor more cables (not shown). It should be noted that although each of thecables 300 a-c is depicted as having connectors on both ends, otherconfigurations of one or more of the cables 300 a-c are possible inwhich there are connectors only on the ends configured to be coupled tothe control box 200.

The head assembly 100 is given its over-the-head physical configurationby the headband 120. Depending on the size of each of the earpieces 110a and 110 b relative to the typical size of the pinna of a human ear,each of the earpieces 110 a and 110 b may be either an “on-ear” (alsocommonly called “supra-aural”) or an “around-ear” (also commonly called“circum-aural”) form of earcup. As will be explained in greater detail,the provision of an acoustic driver 115 a and 115 b in each of theearpieces 110 a and 110 b, respectively, enables the headset 1000 toacoustically output two-channel audio (e.g., stereo audio) to a user.However, it is important to note that it is commonplace for an intercomsystem (e.g., the ICS 800) to provide two-channel audio in which the twochannels of audio do not necessarily represent a common piece of audiowith a relationship such as “left” and “right” that provide a user witha spatial effect (the two channels may be related in other ways, or thevery same audio may be provided on both channels). The microphone boom130 positions the communications microphone 135 in the vicinity of themouth of a user of the headset 1000 when the head assembly 100 iscorrectly worn such that the earpieces 110 a and 110 b overliecorresponding ones of the user's ears. However, despite the depiction inFIG. 1 a of this particular physical configuration of the head assembly100, those skilled in the art will readily recognize that the headassembly may take any of a variety of other physical configurations. Byway of example, alternate embodiments may incorporate a“behind-the-head” or “behind-the-neck” (e.g., what may be called a“napeband”) variant of band in place of the headband 120, may positionthe communications microphone 135 on a portion of one or the other ofthe earpieces 110 a and 110 b (rather than at the end of the microphoneboom 130), and/or may be structured to permit one or both of the cable140 and the microphone boom 130 to be detachable from the earpiece 110 ain order to be attached to the earpiece 110 b (i.e., made “reversible”between left and right sides).

As depicted, the cable 300 a enables the radio 700 to be coupled to theconnector 220 a, the cable 300 b enables the ICS 800 to be coupled tothe connector 220 b (and through the ICS 800, perhaps also the radio850), and the cable 300 c enables either or both of the radio 900 andthe audio source 950 to be coupled to the connector 220 b. The radio 700may be coupled through the cable 300 a to the control box 200, alongwith either the ICS 800 (and perhaps also the radio 850) through thecable 300 b or one or both of the radio 900 and the audio source 950through the cable 300 c. As will be explained in greater detail, mixingcircuitry of the control box 200 enables various forms of mixing ofaudio output by various combinations of these audio devices (i.e., theradio 700, the ICS 800, the radio 850, the radio 900 and the audiosource 950) to the ears of a user of the headset 1000. As will also beexplained in greater detail, the exact manner in which mixing is carriedout changes automatically in response to which ones of these audiodevices are coupled to the control box 200 and/or are active. As will befurther explained in greater detail, a PTT circuit of the control box200 enables a user of the head set 1000 to operate the PTT switch 215 toselect to engage the push-to-talk (PTT) function of one of these audiodevices at times when more than one of these audio devices are coupledto the control box 200, in which the use the PTT function of theselected device to convey their own speech (as detected by thecommunications microphone 135) to other persons. As will be yet furtherexplained in greater detail, the exact manner in which the PTT switch215 is operable to choose what audio device is to have its PTT functionso engaged changes automatically in response to which ones of theseaudio devices are coupled to the control box 200.

It is envisioned that the headset 1000 is well suited for use bypersonnel who both travel in a noisy environment within a vehicle havingthe ICS 800 installed therein to enable communication among them, andalso work collaboratively in a noisy environment outside the vehiclewhile relying on radios (such as the radio 700) carried by each of themto enable communication among them. It is further envisioned thatvehicle may incorporate the vehicle radio 850 (accessible through theICS 800, as will be explained in greater detail), that one or more ofthe personnel may carry another radio (such as the radio 900), and/orthat one or more of the personnel may carry another audio deviceoutputting audio (such as the audio source 950). One example of such useis that of soldiers in a military vehicle (a wheeled vehicle, a vehiclehaving tracks, a helicopter or other flying vehicle, a small motorizedboat, etc.) having the ICS 800, and possibly also the vehicle radio 850.As will be familiar to those skilled in the art of militarycommunications, such vehicles are often noisy inside such that theprovision of the ICS 800 is necessary to enable personnel to hear eachother talking. Further, depending on conditions at a destination reachedby such a vehicle, battlefield sounds and/or physical separation ofpersonnel on patrol or engaged in combat often necessitate the use ofradios carried by each of the personnel to, again, hear each othertalking. Still further, one or more of such personnel may also becarrying another radio to communicate across greater distance to stillother personnel, perhaps personnel in another vehicle (e.g., a pilot ina supporting aircraft). Yet further, one or more of such may also becarrying another device outputting audio (i.e., another audio source)such as a talking global positioning system (GPS) device, etc. However,it should be noted that this envisioned military example is not the onlypossible application of the headset 1000, or of headsets having asimilar configuration. Another envisioned application is that of pilotsand passengers in propeller aircraft or helicopters in which an intercomsystem (e.g., the ICS 800) is also required for such people to hear eachother talking. Further, such people may need to employ radios carried ontheir persons to continue being able to hear each other talking whentheir aircraft is on the ground in a noisy location (perhaps due to therunning of engines and movement of air caused by propellers in motion).

FIG. 1 b depicts an alternate embodiment of the headset 1000 in whichmuch of the functionality and at least some of the components (the typeof components to be presented in greater detail) of the control box 200are incorporated into one or both of the earpieces 110 a and 110 b. Morespecifically, the PTT switch 215 is disposed on one of the earpieces 110a or 110 b, as previously discussed. Further, the connectors 220 a and220 b are disposed at the end of the cable 140, which is depicted asbeing of a Y-cable configuration, although other configurations of thecable 140 to accommodate both of the connectors 220 a and 220 b arepossible, as those skilled in the art will readily recognize.

FIG. 2 a provides an enlarged perspective view of a variant of thecontrol box 200 to more clearly depict various features. As depicted,the casing 210 of the control box 200 may be shaped in a way to enablean almost “pistol-like” grip of the casing 210 in a user's hand suchthat an index and second finger of a user's hand are able to bepositioned over surfaces 216 a and 216 b, respectively, of the PTTswitch 215, while 3rd and 4th fingers are able to be positioned over thesurface 211. The casing 210 also incorporates a removable cover 212providing access to a compartment (not shown) into which a power source290 (e.g., a battery) may be inserted to supply electrical power tocircuits enclosed at least within the casing 210.

The cable 140 extends from a surface 213 of one portion of the casing210 to couple the control box 200 to the head assembly 100, and theconnectors 220 a and 220 b are disposed on a surface 214 of anotherportion of the casing 210. With this arrangement of where the cable 140and the connectors 220 a and 220 b are disposed on the casing 210, thisdepicted variant of the control box 200 is configured to be essentially“in line” with the cable 140 and whatever other cables are coupled tothe connectors 220 a and 220 b. This configuration may be deemedamenable to be held in place against a structural portion of theinterior of an airplane cockpit or to a belt of a user via any of avariety of straps, clips, tapes, adhesives or other hardware (notshown). In an altered form, the cable 140 and both of the connectors 220a and 220 b may be disposed on the portion of the casing 210 (e.g., allon the same surface 213 or 214), which may be deemed amenable to beingheld in place against a component of a piece of machinery or otherdevice carried by a user (e.g., a power tool, a radio, etc.), against acomponent of a vehicle (e.g., clamped to a portion of a steering wheel,or a control column or “yoke” of an airplane, etc.), or in militaryapplications, being somehow mounted to a portion of a gun (e.g., to thestock, the barrel, a handle, etc.) in a manner that allows a militaryuser to operate the PTT switch 215 without taking a hand off the gun.

The PTT switch 215, as depicted, is a 3-position rocker switch havingthe surfaces 216 a and 216 b, and being configured to enable a user toselectively use the push-to-talk function of only one of multiple audiodevices that may be coupled to the connectors 220 a and/or 220 b (e.g.,the radio 700, the radio 900, the ICS 800, or the radio 850 through theICS 800) at any given time. In other words, a user may press their indexfinger against the surface 216 a to move the surface 216 a in a rockingmotion on a pivot of the PTT switch 215 inward (i.e., in a directiongenerally into the casing 210) to one non-center position to select andengage the PTT function of one audio device, or the user may press theirsecond finger against the surface 216 b to move the surface 216 b in anopposing rocking motion on the same pivot of the PTT switch 215 inwardto another non-center position to select and engage the PTT function ofanother audio device. However, as will be familiar to those skilled inthe art of the design of rocker switches, it is not possible to pressboth of the surfaces 216 a and 216 b inward to select and engage the PTTfunction of both audio devices at the same time. Thus, the PTT switch215 serves, by its mechanical design, to limit a user of the headset1000 to engaging the PTT function of only one audio device at a timewithout use of electric power from any power source to do so. Further,as depicted by the arrows, the PTT switch 215 functions as a momentaryswitch when moved to either non-center position in the manner in whichit may be operated to select one or the other of two audio devices, suchthat a user must continuously press (i.e., “hold”) one of the surfaces216 a and 216 b inward to keep the PTT switch 215 at a non-centerposition against a biasing force exerted by a spring (or othercomponent, such as a living hinge—the direction of the biasing forcefrom either non-center position being depicted by the arrows)incorporated into the PTT switch 215 that tends to bias it towards thedepicted center position (and away from either non-center position) inwhich neither of surfaces 216 a or 216 b are pressed inward such that noaudio device is selected. In the more common vernacular of those skilledin the art of the design of switches, the PTT switch 215 is a rockerswitch with a spring-return to its center position and momentary actionwhen operated to be “thrown” in either direction to one of twonon-center positions to select an audio device to engage the PTTfunction of.

FIG. 2 b provides an enlarge perspective view of another variant of thecontrol box 200 to more clearly depict various features, among which isa variant of the PTT switch 215 implemented with a toggle or paddle typeof switch, as opposed to the earlier depicted rocker switch. Asdepicted, the casing 210 of the control box 200 is shaped in a way toenable it to be gripped in a user's hand such that all four fingers(including the index and second fingers) overlie the surface 211, andthe thumb is comfortably positioned to operate the PTT switch 215 bypressing that thumb alternately against one or the other of the surfaces216 a and 216 b. Again, the casing 210 also incorporates a removablecover 212 providing access to a compartment (not shown) into which apower source 290 may be inserted to supply electrical power to circuitsenclosed at least within the casing 210. Also again, the cable 140extends from the surface 213 to couple the control box 200 to the headassembly 100, and the connectors 220 a and 220 b are disposed on thesurface 214.

As has already been depicted with the PTT switch 215 implemented with arocker switch, this depicted variant of the PTT switch 215 is also a3-position switch carrying the surfaces 216 a and 216 b, and beingconfigured to enable a user to selectively use the push-to-talk functionof only one of multiple audio devices that may be coupled to theconnectors 220 a and/or 220 b (e.g., the radio 700, the radio 900, theICS 800, or the radio 850 through the ICS 800) at any given time. Inother words, a user may press their index finger against the surface 216a to move the surface 216 a in a rocking motion on a pivot of the PTTswitch 215 to a non-center position to select and engage the PTTfunction of one audio device, or the user may press their second fingeragainst the surface 216 b to move the surface 216 b in an opposingrocking motion on the same pivot of the PTT switch 215 to anothernon-center position to select and engage the PTT function of anotheraudio device. However, again, it is not possible to press both of thesurfaces 216 a and 216 b to select and engage the PTT function of bothaudio devices at the same time. Also again, the PTT switch 215 functionsas a momentary switch in the manner in which it may be operated toeither one of two non-center positions to select one or the other of twoaudio devices against a biasing force exerted by a spring (or othercomponent, such as a living hinge—the direction of the biasing forcefrom either non-center position being depicted by the arrows))incorporated into the PTT switch 215 that tends to bias it towards thedepicted center position (and away from either non-center position).Again, this variant of the PTT switch has a spring-return to its centerposition and momentary action when operated to be “thrown” in eitherdirection to either non-center position to select an audio device toengage the PTT function of.

FIG. 3 provides a schematic block diagram of portions of a possibleelectrical architecture 2000 that may be employed by the headset 1000.In other words, FIG. 3 provides specific depiction of some conductorsand circuit components that are germane to the presentation andunderstanding of various aspects of the headset 1000, while notspecifically depicting other conductors and circuit components in aneffort to not distract from such presentation and understanding. Forexample, although those killed in the art will readily recognize thatthe acoustic drivers 115 a and 115 b require at least a secondelectrical connection (e.g., to a ground conductor) in addition to aconnection by which audio is conveyed to them, and yet, such a secondelectrical connection is not depicted. Also for example, although thepower source 290 is specifically depicted, its power connections toother components are not depicted to avoid distracting from thedepiction of other conductors more germane to the discussion of what ispresented herein. Further, although the headset 1000 incorporates thecommunications microphone 135 that is meant to be employed in enablingtwo-way audio communications, the communications microphone 135, itssupporting components (e.g., a pre-amplifier, etc.) and its electricalconnections (including the connectors 220 a and 220 b) are not depicted.Thus, this lack of depiction of the communications microphone 135, orits supporting components, or the electrical connections it would likelyhave through the connectors 220 a and 220 b should not be taken as anindication of the microphone 135 not being present or of either thecommunications microphone 135 or its supporting components not drawingelectric power from the same power source(s) from which other componentsof the electrical architecture 2000 that are depicted draw theirelectric power.

As depicted, the depicted portions of the electrical architecture 2000incorporate at least the acoustic drivers 115 a and 115 b; the PTTswitch 215; the connectors 220 a and 220 b; multiple resistors 232 a,232 b, 233, 236 and 258; a pair of audio amplifiers 242 a and 242 b; abypass circuit 243; a PTT circuit 250; and the power source 290. Thepower source 290 provides power to at least the PTT circuit 250 and theaudio amplifiers 242 a and 242 b, despite the lack of specific depictionof power conductors. Together, the resistors 232 a, 232 b, 233 and 236make up a mixing circuit 230. In embodiments of the headset 1000 inwhich the acoustic drivers 115 a and 115 b are disposed within casingsseparate from the mixing circuit 230 and the PTT circuit 250, as mightwell be the case where the control box 200 is not integrated into thehead assembly 100 as depicted in FIG. 1, the acoustic drivers 115 a and115 b may be coupled to much of the rest of what is depicted in FIG. 3through the cable 140. One or more of the bypass circuit 243 and theaudio amplifiers 242 a-b may be disposed either within the casing 210 ora portion of the head assembly 100 such that these components may belocated towards either end of the cable 140. It is for this reason thatthe location of the cable 140 is not depicted relative to othercomponents that are depicted in FIG. 3.

The connectors 220 a and 220 b incorporate ground contacts coupled to aground conductor 221 to which various other components of the headset1000 are also coupled, including the PTT switch 215 and the power source290 (as specifically depicted). The connector 220 a incorporates anaudio contact coupled to an audio conductor 222 a that is coupled to theresistor 232 a, and the connector 220 b incorporates both audio1 andaudio2 contacts coupled to audio conductors 222 b and 223 that arecoupled to the resistors 232 b and 233, respectively. The connector 220a incorporates a radio connect contact coupled to a radio connectconductor 226 a that is coupled to the PTT circuit 250 and to theresistor 236, and the connector 220 b may incorporate a radio connectcontact coupled to a radio connect conductor 226 b that may also becoupled to the PTT circuit 250. Also, the connector 220 b incorporatesan ICS connect contact coupled to an ICS connect conductor 227 that isalso coupled to the PTT circuit 250. The connectors 220 a and 220 b eachincorporate a PTT contact that is coupled to a PTT conductor 228 a and228 b, respectively, that are each separately coupled to the PTT circuit250 and coupled to different contacts of the PTT switch 215. The PTTconductor 228 b is also coupled to the PTT circuit 250 in an additionalcoupling through the resistor 258.

The resistors 232 a and 233 are coupled to each other with their commonnode being further coupled to an input of the audio amplifier 242 a andan input of the bypass circuit 243. The resistors 232 a and 233cooperate to serve as a passive mixer of audio signals received via theaudio conductor 222 a and via the audio2 conductor 223, respectively.The resistors 232 b and 236 are similarly coupled to each other withtheir common node being further coupled to an input of the audioamplifier 242 b and another input of the bypass circuit 243. Theresistors 232 b and 236 function to subject audio signals received viathe audio1 conductor 222 b to the same degree of attenuation to whichaudio signals received via either the audio conductor 222 a or theaudio2 conductor 223 are subjected. This is done to balance theamplitudes of whatever audio is acoustically output to each ear of auser of the headset 1000 by the acoustic drivers 115 a and 115 b. Aswill be explained in greater detail, this balance in amplitude isconstantly maintained by the mixing circuit 230 regardless of what audiodevices are coupled to the connectors 220 a-b and in spite of any lossof power from the power source 290.

Outputs of the audio amplifiers 242 a and 242 b are coupled to theacoustic drivers 115 a and 115 b, respectively. Separate outputs of thebypass circuit 243 are also coupled to each of the acoustic drivers 115a-b. During normal operation of the headset 1000 in which electric poweris being provided to the audio amplifiers 242 a and 242 b by the powersource 290, the audio amplifiers 242 a and 242 b amplify the audiosignals received at their inputs and drive the acoustic drivers 115 aand 115 b, respectively, with amplified forms of those audio signals.Although not specifically shown, a manually-operable control may beincorporated into a portion of the headset 1000 that is coupled to theaudio amplifiers 242 a and 242 b to adjust their gain, and thereby,adjust the amplitude with which the acoustic drivers 115 a and 115 bacoustically output audio to a user of the headset 1000. Duringoperation of the headset 1000 in which electric power is not beingprovided by the power source 290 (e.g., where the power source 290 isdepleted or disconnected from the headset 1000), the audio amplifiers242 a and 242 b may be deprived of power and cease to function toprovide amplification of audio signals. In response to this loss ofelectric power, the bypass circuit 243 electrically couples the commonnode of the resistors 232 a and 233 to the acoustic driver 115 a, andelectrically couples the common node of the resistors 232 b and 236 tothe acoustic driver 115 b, thereby permitting whatever audio devicesthat are coupled to the connectors 220 a and/or 220 b to more directlydrive the acoustic drivers 115 a and/or 115 b with audio signals.

A common contact of the PTT switch 215 is coupled to the groundconductor 221. As previously discussed, the PTT switch 215 is biased bya spring (or living hinge or other mechanism) to a center position inwhich no audio device is selected to engage its PTT function (and awayfrom either of two non-center positions). This position in which noaudio device is selected corresponds to the common contact of the PTTswitch 215 not being coupled to either of the contacts of the PTT switchthat are coupled to either of the PTT conductors 228 a or 228 b.Operation of the PTT switch 215 by a user of the headset 1000 towards anon-center position to select and engage the PTT function of an audiodevice entails the common contact of the PTT switch 215 being coupledwithin the PTT switch 215 to the ground conductor 221, and therebycoupling one or the other of the PTT conductors 228 a and 228 b to theground conductor 221, as well as the corresponding contact of one or theother of the connectors 220 a and 220 b, respectively. The PTT circuit250, which is also coupled to the PTT conductors 228 a and 228 b,monitors the PTT conductors 228 and 228 b for instances of one or theother of these conductors being coupled to the ground conductor 221 byuser operation of the PTT switch 215. During normal operation of theheadset 1000 in which electric power is being provided by the powersource 290 to the PTT circuit 250, the PTT circuit 250 selectivelyaugments the functionality of the PTT switch 215 in enabling a user toselect and engage the PTT function of an audio device in response tovarious conditions that the PTT circuit 250 detects, as will beexplained in greater detail. During operation of the headset 1000 inwhich electric power is not being provided by the power source 290, thePTT circuit 250 may be deprived of power and ceases to function toaugment the functionality of the PTT switch 215 in the various ways thatwill be described. Despite such loss of electric power, the PTT switch215 remains operable to enable a user of the headset 1000 to be moved toeither of two non-center positions to select and engage the PTTfunctionality of either an audio device coupled to the connector 220 aor an audio device coupled to the connector 220 b.

FIGS. 4 a, 4 b, 4 c, 4 d and 4 e, taken together, depict variouspossible coupling configurations of the headset 1000 in which differentpossible ones or possible combinations of the cables 300 a-c, anddifferent possible ones or possible combinations of audio devices arecoupled to the connectors 220 a and/or 220 b of the headset 1000. Itshould be noted that what is depicted in all of FIGS. 4 a-e is a subsetof the portion of the electrical architecture 2000 that is depicted inFIG. 3. For the sake of reducing distraction and to enhance ease ofunderstanding, this subset excludes some components that were depictedin FIG. 3, but which are not as germane to what is presented anddiscussed with regard to FIGS. 4 a-e. FIGS. 4 a-e and the following textthat accompanies these figures are centered more on aspects of theinteractions between various audio devices and various components of themixing circuit 230 and the PTT circuit 250.

FIG. 4 a depicts a coupling configuration in which the radio 700 iscoupled to the connector 220 a via the cable 300 a, with no cable oraudio device being coupled to the connector 220 b. With the coupling ofthe cable 300 a to the connector 220 a, the radio connect conductor 226a is coupled to the ground conductor 221 in a conductive loop formedwithin the cable 300 a. This grounding of the radio connect conductor226 a provides the PTT circuit 250 with an indication of the connectionof at least the cable 300 a to the connector 220 a, thereby providingthe PTT circuit 250 with an indication of there being an audio devicecapable of two-way audio communications (such as a radio) to theconnector 220 a. With the coupling of the radio 700 to the connector 220a via the cable 300 a, the radio 700 is coupled to the ground conductor221, the audio conductor 222 a and the PTT conductor 228 a through thecable 300 a.

With all of these couplings made, the radio 700 is able to output anaudio signal to the audio conductor 222 a, which conveys the audiosignal to the audio amplifier 242 a and the bypass circuit 243 throughthe resistor 232 a. Each of the resistors 232 a and 233 preferably has arelatively small impedance (e.g., perhaps in the range of 10 ohms to 100ohms, or thereabouts). With no audio device coupled to the connector 220b, the audio2 conductor 223 is not coupled to an audio device, resultingin the resistor 233 effectively presenting an infinite impedance at thecommon node of the resistors 232 a and 233, despite its own smallimpedance. Thus, given the relatively high impedance of the input to theamplifier 242 a (e.g., perhaps 10 Kohms to 100 Kohms), the audio signalconveyed via the audio conductor 222 a is attenuated by the resistor 232a to only a relative minor degree, at most. With no audio device coupledto the connector 220 b, no audio signal is provided on the audio1conductor 222 b, at all, and therefore, no audio is acoustically outputby the acoustic driver 115 b.

At times when a user of the headset 1000 wishes to engage the PTTfunction of the radio 700 to wirelessly transmit their voice to someoneelse, the user may operate the PTT switch 215 to a non-center positionto cause the ground conductor 221 to be coupled to the PTT conductor 228a, which in turn, grounds a PTT input to a PTT circuit (not shown) ofthe radio 700 that is coupled via the cable 300 a to the PTT conductor228 a. As those familiar with common practices in the design of two-wayradios (including portable radios supporting two-way audiocommunications) will readily recognize, it is common practice toremotely cause a coupling of an input to a two-way radio to a groundconductor cause the PTT function of that radio to be engaged.

With no other audio device coupled to the connector 220 b, thepossibility exists that a user of the headset 1000 may become confusedabout which way to operate the PTT switch 215 (i.e., which non-centerposition to operate the PTT switch 215 towards) to select and engage thePTT function of the radio 700, and may mistakenly operate the PTT switch215 in a wrong way (i.e., to a wrong non-center position) that uselesslycouples the PTT conductor 228 b to the ground conductor 221, instead ofcoupling the PTT conductor 228 a to the ground conductor 221. As aresult, the user may begin speaking into the communications microphone135 (refer to FIG. 1) with the mistaken belief that they aretransmitting their voice through the radio 700. To counteract thispossible mistake that may be made by a user, the PTT circuit 250 is ableto continuously monitor the radio connect conductors 226 a and 226 b, aswell as the ICS connect conductor 227 to determine what audio devicesare connected to the connectors 220 a and 220 b at any given time, andis able to augment the operation of the PTT switch 215 in ways thatserve to address such concerns.

More specifically, the PTT circuit 250 monitors each of the radioconnect conductors 226 a and 226 b for instances of either of theseconductors being coupled to the ground conductor 221, which wouldindicate the connection of a radio to one or both of the connectors 220a and 220 b, respectively. Further, the PTT circuit 250 monitors the ICSconnect conductor 227 for instances of it being coupled to a positivevoltage relative to the ground conductor 221 (e.g., +12V). With theradio 700 coupled to the connector 220 a through the cable 300 a, andwith nothing coupled to the connector 220 b, the PTT circuit 250 detectsthe coupling of the radio connect conductor 226 a to the groundconductor 221, and detects the lack of a coupling of either the radioconnect conductor 226 b to the ground conductor 221 or the ICS connectconductor 227 to such a positive voltage. In response to thesecircumstances, the PTT circuit 250 augments the operation of the PTTswitch 215 such that if a user of the headset mistakenly operates thePTT switch 215 to a wrong non-center position such that the PTTconductor 228 b is coupled to the ground conductor 221 (instead ofgrounding the PTT conductor 228 a), the PTT circuit 250 responds to thecoupling of the PTT conductor 228 b to ground by coupling the PTTconductor 228 a to the ground conductor, itself, to provide the radio700 with this otherwise missing indication to cause the PTT function ofthe radio 700 to be engaged. Thus, the user of the headset 1000 is ableto cause their voice to be transmitted by the radio 700 to someone else,regardless of which way they operate the PTT switch 215 (i.e.,regardless of which non-center position the PTT switch 215 is operatedtowards).

FIG. 4 b depicts a coupling configuration in which the ICS 800 iscoupled to the connector 220 b via the cable 300 b, with no cable oraudio device being coupled to the connector 220 a. With the coupling ofthe ICS 800 to the connector 220 b via the cable 300 b, the ICS 800 iscoupled to the ground conductor 221, the audio1 conductor 222 b, theaudio2 conductor 223, the ICS connect conductor 227 and the PTTconductor 228 b through the cable 300 b.

With all of these couplings made, the ICS 800 is able to output audiosignals to the audio1 conductor 222 b and the audio2 conductor 223,which convey these audio signals to the audio amplifiers 242 a and 242 bthrough the resistors 232 b and 233, respectively, as well as to thebypass circuit 243. As with the resistors 232 a and 233, preferably,each of the resistors 232 b and 236 has a relatively small impedance(e.g., perhaps in the range of 10 ohms to 100 ohms, or thereabouts).With no audio device coupled to the connector 220 a, the audio conductor222 a is not coupled to an audio device and the radio connect conductor226 is not coupled to the ground conductor 221, resulting in theresistor 232 a effectively presenting an infinite impedance at thecommon node of the resistors 232 a and 233, and in the resistor 236similarly presenting an infinite impedance at the common node of theresistors 232 b and 236. Again, given the relatively high impedances ofthe inputs to the amplifiers 242 a and 242 b, the audio signals conveyedvia the audio1 conductor 222 b and the audio2 conductors 223 areattenuated by the resistors 232 b and 233, respectively, to only a minordegree. With no audio device coupled to the connector 220 a, only audioprovided by the ICS 800 through the connector 220 b is acousticallyoutput by the acoustic drivers 115 a and 115 b.

At times when a user of the headset 1000 wishes to engage the PTTfunction of the ICS 800 to wirelessly transmit their voice to someoneelse, the user may operate the PTT switch 215 to cause the groundconductor 221 to be coupled to the PTT conductor 228 b, which in turn,grounds a PTT input to a PTT circuit (not shown) of the ICS 800 that iscoupled via the cable 300 b to the PTT conductor 228 b. As thosefamiliar with common practices in the design of vehicle intercom systemswill readily recognize, it is common practice to couple a vehicleintercom system to a vehicle radio to enable a user of a headset coupledto a vehicle intercom system to be able to use such a vehicle radiothrough that vehicle intercom system. To enable a user of a vehicleintercom system that is also coupled to a vehicle radio to selectbetween engaging the PTT function of the vehicle intercom system and thePTT function of the vehicle radio, a widely accepted approach tooperating a PTT signal input to such a vehicle intercom system to signalwhether to engage the PTT function of one or the other has arisen overtime in which that signal input is coupled directly to a groundconductor to engage the PTT function of the vehicle radio, and iscoupled to ground through a 470 ohm resistor to engage the PTT functionof the vehicle intercom system.

With no other audio device coupled to the connector 220 a, the PTTconductor 228 a is not coupled to an input of any audio device, and soif the user operates the PTT switch 215 in a manner that couples the PTTconductor 228 a to the ground conductor 221, nothing is signaled to anyaudio device. To counteract this situation in which such operation ofthe PTT switch 215 serves no purpose and to enable a user of the headset1000 to choose between engaging the PTT function of either the ICS 800or the vehicle radio 850 coupled to the ICS 800 (if the vehicle radio850 is present and coupled to the ICS 800), the PTT circuit 250 is againable to augment the operation of the PTT switch 215, and to do soautomatically without user input to trigger it to do so.

Again, the PTT circuit 250 monitors each of the radio connect conductors226 a and 226 b for instances of either of these conductors beingcoupled to the ground conductor 221, and monitors the ICS connectconductor 227 for instances of it being coupled to a positive voltagerelative to the ground conductor 221. With the ICS 800 coupled to theconnector 220 b through the cable 300 b, and with nothing coupled to theconnector 220 a, the PTT circuit 250 detects the coupling of the ICSconnect conductor 227 to a positive voltage relative to the groundconductor 221 (provided by a power source 827 of the ICS 800), anddetects the lack of a coupling of either the radio connect conductors226 a or 226 b to the ground conductor 221. In response to thesecircumstances, the PTT circuit 250 augments the operation of the PTTswitch 215 to allow the user to select and engage the PTT function ofthe ICS 800 by operating the PTT switch 215 to couple the PTT conductor228 a to the ground conductor 221 (instead of grounding the PTTconductor 228 b). The PTT circuit 250 monitors the PTT conductor 228 aand responds to its being coupled to the ground conductor 221 by theuser's use of the PTT switch 215 by coupling the PTT conductor 228 b tothe ground conductor 221 through the resistor 258, which is a 470 ohmresistor that provides the ICS 800 with the correct indication requiredto cause the PTT function of the ICS 800 to be engaged. Thus, the useris enabled by this augmented function of the PTT switch 215 to selectand engage the PTT function of one or the other of the ICS 800 and thevehicle radio 850 depending on how they operate the PTT switch 215(i.e., depending on which non-center position the PTT switch 215 isoperated towards by the user).

FIG. 4 c depicts a coupling configuration in which one or both of theradio 900 and the audio source 950 are coupled to the connector 220 bvia the cable 300 c, with no cable or audio device being coupled to theconnector 220 a. With the coupling of the cable 300 c to the connector220 a, the radio connect conductor 226 b is also coupled to the groundconductor 221 in a conductive loop formed within the cable 300 c. Thegrounding of the radio connect conductor 226 b provides the PTT circuit250 with an indication of the connection of at least the cable 300 c tothe connector 220 b, thereby providing the PTT circuit 250 with anindication of there being an audio device capable of two-way audiocommunications (such as a radio) to the connector 220 b. Where the radio900 is coupled to the connector 220 b via the cable 300 c, the radio 900is coupled to the ground conductor 221, the audio1 conductor 222 b andthe PTT conductor 228 b through the cable 300 c. Where the audio source950 is coupled to the connector 220 b via the cable 300 c, the audiosource 950 is coupled to the ground conductor 221 and the audio2conductor 223.

With all of these couplings made, the radio 900 (if present) is able tooutput an audio signal to the audio1 conductor 222 b, which conveys theaudio signal to the audio amplifier 242 b and the bypass circuit 243through the resistor 232 b. Also, with all of these couplings made, theaudio source 950 (if present) is able to output an audio signal to theaudio2 conductor 223, which conveys the audio signal to the audioamplifier 242 a and the bypass circuit 243 through the resistor 233.Again, with no audio device coupled to the connector 220 a, the audioconductor 222 a is not coupled to any source of audio and the radioconnector conductor 226 is not coupled to the ground conductor 221.Thus, the resistors 232 a and 236 are caused to effectively presentinfinite impedances, and the resistors 232 b and 233 imposed little, ifany, attenuation on audio signals conveyed via the audio1 conductor 222b and the audio2 conductor 223. Therefore, only audio provided by theaudio source 950 and the radio 900 through the connector 220 b isacoustically output by the acoustic drivers 115 a and 115 b,respectively.

At times when a user of the headset 1000 wishes to engage the PTTfunction of the radio 900 to wirelessly transmit their voice to someoneelse, the user may operate the PTT switch 215 to cause the groundconductor 221 to be coupled to the PTT conductor 228 b, which in turn,grounds a PTT input to a PTT circuit (not shown) of the radio 900 thatis coupled via the cable 300 c to the PTT conductor 228 b.

With no other audio device coupled to the connector 220 a, thepossibility exists that a user of the headset 1000 may become confusedabout which way to operate the PTT switch 215 to select and engage thePTT function of the radio 900, and may mistakenly operate the PTT switch215 in a wrong way (i.e., towards a wrong non-center position) thatuselessly couples the PTT conductor 228 a to the ground conductor 221,instead of coupling the PTT conductor 228 b to the ground conductor 221.To counteract this possible mistake that may be made by a user, the PTTcircuit 250 is again able to augment the operation of the PTT switch 215in ways that serve to address such concerns.

Again, the PTT circuit 250 monitors each of the radio connect conductors226 a and 226 b for instances of either of these conductors beingcoupled to the ground conductor 221, and monitors the ICS connectconductor 227 for instances of it being coupled to a positive voltagerelative to the ground conductor 221. With the radio 900 coupled to theconnector 220 b through the cable 300 c, and with nothing coupled to theconnector 220 a, the PTT circuit 250 detects the coupling of the radioconnect conductor 226 b to the ground conductor 221, and detects thelack of a coupling of either the radio connect conductor 226 a to theground conductor 221 or the ICS connect conductor 227 to such a positivevoltage. In response to these circumstances, the PTT circuit 250augments the operation of the PTT switch 215 such that if a user of theheadset mistakenly operates the PTT switch 215 such that the PTTconductor 228 a is coupled to the ground conductor 221 (instead ofcoupling the PTT conductor 228 b to the ground conductor 221), the PTTcircuit 250 responds to the coupling of the PTT conductor 228 a to theground conductor 221 by coupling the PTT conductor 228 b to the groundconductor 221, itself, to provide the radio 900 with the otherwisemissing indication to cause the PTT function of the radio 900 to beengaged. Thus, the user of the headset 1000 is able to cause their voiceto be transmitted by the radio 900 to someone else, regardless of whichway they operate the PTT switch 215 (i.e., regardless of whichnon-center position they operate the PTT switch 215 towards).

Unlike the coupling configurations depicted in FIGS. 4 a-c in whichaudio devices were coupled to only one of the connectors 220 a and 220 bat any time, the coupling configurations depicted in FIG. 4 d-e haveaudio devices coupled to both of the connectors 220 a and 220 b,simultaneously. As will be made clear, whereas the mixing circuit 230did not perform any mixing of audio signals from multiple audio devicesin the coupling configurations of FIGS. 4 a-c, in response to thesimultaneous coupling of audio devices to both of these connectors inthe coupling configurations of FIGS. 4 d-e, the mixing circuit 230 mixesaudio signals provided by multiple audio devices. As will also be madeclear, whereas the PTT circuit 250 responded to the connection of audiodevices to one of the connectors 220 a and 220 b by augmenting thefunctionality of the PTT switch 215 to improve its use with audiodevices coupled to only one of these connectors, in response to thesimultaneous coupling of audio devices to both of these connectors, thePTT ceases to augment the functionality of the PTT switch 215. Thus, aswill be made clear, the mixing circuit 230 and the PTT circuit 250 havedistinct modes in which they function differently at least partly inresponse to whether audio devices are coupled to one or both of theconnectors 220 a and 220 b. Also, as is made clear in the couplingconfigurations depicted in each of FIGS. 4 a-c, the nature of theaugmentation of functionality of the PTT switch 215 provided by the PTTcircuit 250 changed in response to the type of audio device coupled toone or the other of the connectors 220 a and 220 b, and in response towhich of these connectors an audio device is coupled. These changes inthe functionality provided by the mixing circuit 230 and the PTT circuit250 are automatic in the sense that a user of the headset 1000 need notoperate any form of manually-operable control to cause these changes tooccur. Instead, the user simply couples the headset 1000 to whateveraudio devices the user chooses, and the mixing circuit 230 and the PTTcircuit 250 change their functional behavior based solely on what audiodevices have been coupled to the headset 1000 and to which of theconnectors 220 a and 220 b.

FIG. 4 d depicts a coupling configuration in which the radio 700 iscoupled to the connector 220 a via the cable 300 a and the ICS 800 iscoupled to the connector 220 b via the cable 300 b. With the coupling ofthe cable 300 a to the connector 220 a, the radio connect conductor 226a is coupled to the ground conductor 221 in a conductive loop formedwithin the cable 300 a. With the coupling of the radio 700 to theconnector 220 a via the cable 300 a, the radio 700 is coupled to theground conductor 221, the audio conductor 222 a and the PTT conductor228 a through the cable 300 a. With the coupling of the ICS 800 to theconnector 220 b via the cable 300 b, the ICS 800 is coupled to theground conductor 221, the audio1 conductor 222 b, the audio2 conductor223, the ICS connect conductor 227 and the PTT conductor 228 b throughthe cable 300 b. The radio connect conductor 226 b of the connector 220b is not coupled.

With all of these couplings made, the radio 700 is able to output anaudio signal to the audio conductor 222 a, and the ICS 800 is able tooutput audio signals to the audio1 conductor 222 b and the audio2conductor 223. With audio signals being provided on both the audioconductor 222 a and the audio2 conductor 223, the resistors 232 a and233 cooperate as a passive mixer to mix the audio signals provided onthese two conductors, with the resulting mixed audio signal beingconveyed from the common node of these two resistors to the acousticdriver 115 a through the audio amplifier 242 a or the bypass circuit243, as previously discussed. As those familiar with the electricalcharacteristics of audio signals typically output by such audio devicesas radios and intercom systems will readily recognize, such an audiosignal can be regarded as being driven by a voltage source incorporatedinto the audio device that outputs that audio signal. Thus, as depicted,the radio 700 can be regarded as driving the audio conductor 222 a witha voltage source 722, and the ICS 800 can be regarded as driving theaudio1 conductor 222 b and the audio2 conductor 223 with voltage sources822 and 823, respectively, all of which have one of their outputterminals coupled to the ground conductor 221. As those skilled in theart will readily recognize, such voltage sources typically have littleor no resistance between their output terminals such that each of thevoltage sources 722, 822 and 823 can almost be regarded as a short tothe ground conductor 221. Thus, with both the audio conductor 222 a andthe audio2 conductor 223 being coupled to such audio sources (which canbe regarded as powers sources with low impedance), each one of theseconductors and their associated audio source effectively completes anattenuating network through the other of these conductors and itsassociated audio source. The result is a mutual attenuating current floweffect that enables the cooperation of the resistors 232 a and 233 tofunction as a passive mixer of the audio signals provided via these twoconductors.

In a very similar way, with an audio signal being provided on the audioconductor 222 b and with the radio connect conductor 226 a being coupledto the ground conductor 221, the resistors 232 b and 236 cooperate in amanner very much like the resistors 232 a and 233, essentially asanother passive mixer to mix the audio provided on the audio conductor222 b with the ground coupling provided through the radio connectconductor 226 a, with the resulting mixed audio signal being conveyedfrom the common node of these two resistors to the acoustic driver 115 bthrough the audio amplifier 242 b or the bypass circuit 243, aspreviously discussed.

Beyond simply mixing audio signals, the manner in which the resistors232 a and 233 are coupled together and cooperate, and the manner inwhich the resistors 232 b and 236 are coupled together and cooperateresult in the mixing circuit 230 serving to aid in balancing theamplitudes of all three of the audio signals provided on the audioconductor 222 a, the audio1 conductor 222 b and the audio2 conductor223. Indeed, to enable this balancing, it is preferred that all four ofthe resistors 232 a, 232 b, 233 and 236 have the same resistive value(i.e., a common resistance R, as depicted). As a result, the amplitudeof the audio acoustically output to the ears of a user of the headset1000 is balanced between what is acoustically output to one ear versuswhat is acoustically output to the other. The manner in which theseresistors are coupled together and cooperate also serve to provide anadvantageous proportion of mixing between the audio signals provided onthe audio conductor 222 a and the audio2 conductor 223, such that oneear of a user is provided with an even mixture of these two audiosignals, while the other ear is provided solely with the audio signalprovided on the audio1 conductor 222 b. It has been determined to bedesirable to generally provide audio from each radio to only one ear ofa user, while providing audio from an intercom system to both ears. Thishas been found to be advantageous in enabling a user to quicklydistinguish things said to the user by individuals over a radio who areprobably at a location where the user cannot see those individuals fromthings said to the user by individuals over an intercom system who areprobably in the same vehicle with user (or otherwise in close proximitywith the user such that the user is able to see them). It has also beendetermined to be desirable to provide audio from two different radios toseparate ears of a user, as it has been found to be advantageous inenabling a user to quickly determine which radio a user is hearingsomeone through so as to more easily maintain a clear mental picture ofthe locations of different individuals who may be talking to the user atthe same time. Further, this use of these resistors in forming passivemixers enables the mixing circuit 230 to function without electric powerfrom the power source 290 (or any other power source) such that loss ofelectric power will not impair the operation of the mixing circuit 230.

With the coupling of audio devices to both of the connectors 220 a and220 b, the PTT circuit 250 generally responds by ceasing to augment thefunctionality of the PTT switch 215. More precisely, the PTT circuit 250detects the coupling of the ICS connect conductor 227 to a positivevoltage relative to the ground conductor 221, detects the coupling ofthe radio connect conductor 226 a to the ground conductor 221, anddetermines that audio devices supporting two-way audio communicationshave been coupled to each of the connectors 220 a and 220 b. Inresponse, the PTT circuit 250 refrains from augmenting the functionalityof the PTT switch 215. This enables a user of the headset 1000 to simplyoperate the PTT switch 215 towards one non-center position or the otherto couple the ground conductor 221 to either the PTT conductor 228 a toengage the PTT function of the radio 700 or the PTT conductor 228 b toengage the PTT function of the radio 850 (through the ICS 800).

FIG. 4 e depicts a coupling configuration in which the radio 700 iscoupled to the connector 220 a via the cable 300 a, and in which one orboth of the radio 900 and the audio source 950 are coupled to theconnector 220 b via the cable 300 c. With the coupling of the cables 300a and 300 c to the connectors 220 a and 220 b, respectively, the radioconnect conductors 226 a and 226 b are both coupled to the groundconductor 221 in conductive loops formed within the cables 300 a and 300c, respectively. With the coupling of the radio 700 to the connector 220a via the cable 300 a, the radio 700 is coupled to the ground conductor221, the audio conductor 222 a and the PTT conductor 228 a through thecable 300 a. Where the radio 900 is coupled to the connector 220 b viathe cable 300 c, the radio 900 is coupled to the ground conductor 221,the audio1 conductor 222 b and the PTT conductor 228 b through the cable300 c. Where the audio source 950 is coupled to the connector 220 b viathe cable 300 c, the audio source 950 is coupled to the ground conductor221 and the audio2 conductor 223. The ICS connect conductor 227 of theconnector 220 b is not coupled.

With all of these couplings made, the radio 700 is able to output anaudio signal to the audio conductor 222 a, the radio 900 (if present) isable to output an audio signal to the audio1 conductor 222 b, and theaudio source 950 (if present) is able to output an audio signal to theaudio2 conductor 223. With audio signals being provided on both theaudio conductor 222 a and the audio2 conductor 223, the resistors 232 aand 233 cooperate as a passive mixer to mix the audio signals providedon these two conductors, with the resulting mixed audio signal beingconveyed from the common node of these two resistors to the acousticdriver 115 a through the audio amplifier 242 a or the bypass circuit243, as previously discussed at length in reference to FIG. 4 d. Also,with an audio signal being provided on the audio conductor 222 b andwith the radio connect conductor 226 a being coupled to the groundconductor 221, the resistors 232 b and 236 cooperate in a manner verymuch like the resistors 232 a and 233, essentially as another passivemixer to mix the audio provided on the audio conductor 222 b with thecoupling to the ground conductor 221 provided through the radio connectconductor 226 a, with the resulting mixed audio signal being conveyedfrom the common node of these two resistors to the acoustic driver 115 bthrough the audio amplifier 242 b or the bypass circuit 243, as alsopreviously discussed at length in reference to FIG. 4 d.

Where the audio source 950 is present, the manner in which the resistors232 a and 233 are coupled together and cooperate also serve to providean advantageous proportion of mixing between the audio signals providedon the audio conductor 222 a and the audio2 conductor 223, such that oneear of a user is provided with an even mixture of these two audiosignals. As previously discussed, the audio source 950 may any of avariety of audio devices, i.e., devices providing an audio output,including and not limited to, a talking GPS device, a talkingenvironmental sensing device (e.g., a talking chemical, biological orradiological hazard sensing device), etc. Where the radio 900 ispresent, the other ear is provided solely with the audio signal providedon the audio1 conductor 222 b. Again, where the radio 900 is presentalong with the radio 700 such that a user of the headset 1000 isinteracting with both radios, it has been determined to be desirable togenerally provide audio from each of these radios to only one ear (aseparate ear for each) of a user. Again, this has been found to beadvantageous in enabling a user to quickly determine which radio a useris hearing someone through so as to more easily maintain a clear mentalpicture of the locations of different individuals who may be talking tothe user at the same time.

With the coupling of audio devices to both of the connectors 220 a and220 b, the PTT circuit 250 generally responds by ceasing to augment thefunctionality of the PTT switch 215. More precisely, the PTT circuit 250detects the coupling of both of the radio connect conductors 226 a and226 b to the ground conductor 221, and determines that audio devicessupporting two-way audio communications have been coupled to each of theconnectors 220 a and 220 b. In response, the PTT circuit 250 refrainsfrom augmenting the functionality of the PTT switch 215. This enables auser of the headset 1000 to simply operate the PTT switch 215 towardsone non-center position or another to couple the ground conductor 221 toeither the PTT conductor 228 a to engage the PTT function of the radio700 or the PTT conductor 228 b to engage the PTT function of the radio900 (if present).

Although much of the discussion herein has been focused on the depictedexample of the headset 1000, in which all three of the passive mixer230, the PTT switch 215, and the PTT circuit 250 have been depicted anddiscussed as being present in the same device, it is important to note(and it will be readily appreciated by those skilled in the art) thateach of the passive mixer 230, the PTT switch 215 and the PTT circuit250 may be separately incorporated into different devices, or one ofthese three may be absent in a device into which the other two areincorporated. In other words, this presentation of all three of thepassive mixer 230, the PTT switch 215 and the PTT circuit 250 into thesame headset 1000 is meant to serve only as a single example that ispresented to facilitate providing an explanation of the structure andfunction of each, and should not be taken as indicating that any one ofthese necessarily requires one or both of the others. For example, andas suggested by FIGS. 5 a and 6 a, it is envisioned that the passivemixer 230 may be employed in headphones that provide no facility,whatsoever, for the user of the headphones to engage any PTT function ofany device to which those headphones may be coupled. Also for example,and as suggested by FIGS. 5 b and 6 b, it is envisioned that the PTTcircuit 250 may be employed with a hand-held microphone or a microphoneon a desk stand at a radio station or other environment with stationaryspeakers being provided in place of any form of headphones or headsetsfor listening to received radio signals.

It should also be noted that although the radios 700 and 900 arepresented as coupling a conductor coupled to one or the other of theconnectors 220 a and 220 b to the ground conductor 221 when coupled toone of these connectors, and although the ICS 800 is presented ascoupling a conductor coupled to the connector 220 b to a power source ofthe ICS 800 when coupled to the connector 220 b, these choices of mannerin which the coupling of the radio 700, the radio 900 and the ICS 800 issignaled to the PTT circuit 250 representing arbitrary choices. Morespecifically, other embodiments are possible in which one of the radio700 or 900 couples a conductor that is coupled to one or the other ofthe connectors 220 a and 220 b to a power source of that one of theradio 700 or 900 when that one of the radio 700 or 900 is coupled tothat one of the connectors 220 a and 220 b. However, it is deemedpreferable to avoid the possibility of draining the often very limitedpower sources of a radio, especially a portable radio, allowing anycomponent of the headset 1000 (including the PTT circuit 250) to drawpower from such power sources. In contrast, it is deemed desirable toallow the ICS 800 to provide a coupling to a power source of the ICS 800when coupled to the headset 1000. In addition to the provision of powerserving as a signal to the PTT circuit 250 that the ICS 800 is coupledto the headset 1000, the fact the ICS 800 is likely to have access to amuch higher capacity power supply of a vehicle makes it potentiallydesirable to draw electric power from the ICS 800 in lieu of depletingthe power source 290, which may also be of highly limited capacity.

FIG. 5 a depicts a variant of the electrical architecture 2000 of FIG. 3in which an alternate form of the mixing circuit 230 is depicted, aswell as the audio amplifiers 242 a and 242 b, the bypass circuit 243 andthe acoustic drivers 115 a and 115 b. Also depicted are the connectors220 a and 220 b, along with an additional connectors 220 x. In thisdepicted alternate form of the mixing circuit 230, the resistor 236 thathad been coupled to the radio coupled conductor 226 a is, instead,coupled through to an audio conductor 229 to a corresponding audiocontact of the connector 229. In this way, the mixing circuit 230 may beemployed to mix the audio of an ICS (e.g., the ICS 800) coupled to theconnector 220 b and up to two radios (e.g., the radios 700 and 900)separately coupled to the connectors 220 a and 220 x such that the audioof a radio coupled to the connector 220 a is mixed with one channel ofaudio of an ICS coupled to the connector 220 b for acoustic output bythe acoustic driver 115 a, and such that the audio of a radio coupled tothe connector 22 x is mixed with the other channel of audio of an ICScoupled to the connector 220 b for acoustic output by the acousticdriver 115 b.

FIG. 5 b depicts a variant of the electrical architecture 2000 of FIG. 3in which audio mixing functionality is not provided, and in which thePTT circuit 250 either may or may not present (as suggested the PTTcircuit 250 and associated resistor being depicted with dotted lines).

FIG. 6 a depicts a variant of the head assembly 100 of FIG. 1 b intowhich the communications microphone 135 is not incorporated. Thisdepiction of this variant is intended to make clear that thefunctionality of the PTT switch 215 and possibly also of the mixingcircuit 230 (which if present, may be incorporated into a portion of thehead assembly 100) need not be accompanied by the communicationsmicrophone 135, which may be incorporated into a separate device.

FIG. 6 b depicts a hand-held microphone 150 into which at least the PTTswitch 215 is incorporated, perhaps also with the PTT circuit 250. Thisdepiction of this hand-held microphone is intended to make clear thatthe functionality of the PTT switch 215 and possibly also of the PTTcircuit 250 (which if present, may be incorporated into the hand-heldmicrophone 150) need not be accompanied by the mixing circuit 230.

It should be still further noted that although much of what has beendepicted and discussed herein entails wired connections between devicesand/or components of devices having one or more of the passive mixer230, the PTT switch 215 and the PTT circuit 250, embodiments in whichwireless (e.g., radio frequency or infrared) communications are employedin place of one or more of such wired connections. By way of example, analternate form of the control box 200 may be coupled to one or moreother components of the headset 1000 via a wireless linkage, therebyallowing the control box 200 to be mounted to a piece of machinery, alocation in the interior of a vehicle, or on a portion of a weapon in amanner that does not encumber a user of the headset 1000 with a wiredconnection to the control box 200.

Other embodiments and implementations are within the scope of thefollowing claims and other claims to which the applicant may beentitled.

1. An apparatus comprising: a first connector to enable the coupling ofa first audio device to the apparatus; a second connector to enable thecoupling of a second audio device to the apparatus; and a push-to-talk(PTT) switch having a center position, operable to a first non-centerposition from the center position to engage a PTT function of the firstaudio device at a time when the first audio device is coupled to theapparatus, operable to a second non-center position from the centerposition to engage a PTT function of the second audio device at a timewhen the second audio device is coupled to the apparatus, mechanicallystructured to prevent the PTT functions of both of the first and secondaudio devices from being simultaneously engaged, and in which a biasingforce tends to bias the PTT switch towards the center position from thefirst and second non-center positions.
 2. The apparatus of claim 1,wherein the PTT switch comprises a rocker switch having a first surfaceand a second surface, wherein the PTT switch is operable to the firstnon-center position by pressing on the first surface and is operable tothe second non-center position by pressing on the second surface.
 3. Theapparatus of claim 1, wherein the PTT switch further comprises a springproviding at least a portion of the biasing force to tend to bias thePTT switch toward the center position from at least one of the first andsecond non-center positions.
 4. The apparatus of claim 1, furthercomprising a communications microphone to detect speech to be conveyedto at a remotely located person through the PTT function of one of thefirst and second audio devices of which the PTT function is engagedthrough operation of the PTT switch.
 5. The apparatus of claim 1,wherein the apparatus comprises a headset having at least one acousticdriver structured to be positioned adjacent at least one ear of a userof the apparatus at a time when the apparatus is worn on the user's headto acoustically output audio provided by at least one of the first andsecond audio devices.
 6. The apparatus of claim 5, wherein the PTTswitch is disposed on a casing of the headset in which the acousticdriver is disposed.
 7. The apparatus of claim 5, further comprising acontrol box on which the PTT switch is disposed and coupled to a casingof the headset in which the acoustic driver is disposed by a cable. 8.The apparatus of claim 5, further comprising a control box on which thePTT switch is disposed and coupled to a casing of the headset in whichthe acoustic driver is disposed by a wireless connection.
 9. Anapparatus comprising: a first radio; a second radio; and a push-to-talk(PTT) switch having a center position, operable to a first non-centerposition from the center position to engage a PTT function of the firstradio, operable to a second non-center position from the center positionto engage a PTT function of the second radio, mechanically structured toprevent the PTT functions of both of the first and second radios frombeing simultaneously engaged, and in which a biasing force tends to biasthe PTT switch towards the center position from the first and secondnon-center positions.
 10. The apparatus of claim 9, wherein the PTTswitch comprises a rocker switch having a first surface and a secondsurface, wherein the PTT switch is operable to the first non-centerposition by pressing on the first surface and is operable to the secondnon-center position by pressing on the second surface.
 11. The apparatusof claim 9, wherein the PTT switch further comprises a spring providingat least a portion of the biasing force to tend to bias the PTT switchtoward the center position from at least one of the first and secondnon-center positions.
 12. The apparatus of claim 9, further comprising acommunications microphone to detect speech to be conveyed to at aremotely located person through the PTT function of one of the first andsecond radios of which the PTT function is engaged through operation ofthe PTT switch.
 13. The apparatus of claim 9, wherein the apparatuscomprises a headset having at least one acoustic driver structured to bepositioned adjacent at least one ear of a user of the apparatus at atime when the apparatus is worn on the user's head to acousticallyoutput audio provided by at least one of the first and second radios.14. The apparatus of claim 13, wherein the PTT switch is disposed on acasing of the headset in which the acoustic driver is disposed.
 15. Anapparatus comprising: a radio; an intercom system (ICS); and apush-to-talk (PTT) switch having a center position, operable to a firstnon-center position from the center position to engage a PTT function ofthe radio, operable to a second non-center position from the centerposition to engage a PTT function of the ICS, mechanically structured toprevent the PTT functions of both of the radio and the ICS from beingsimultaneously engaged, and in which a biasing force tends to bias thePTT switch towards the center position from the first and secondnon-center positions.
 16. The apparatus of claim 15, wherein the PTTswitch comprises a rocker switch having a first surface and a secondsurface, wherein the PTT switch is operable to the first non-centerposition by pressing on the first surface and is operable to the secondnon-center position by pressing on the second surface.
 17. The apparatusof claim 15, wherein the PTT switch further comprises a spring providingat least a portion of the biasing force to tend to bias the PTT switchtoward the center position from at least one of the first and secondnon-center positions.
 18. The apparatus of claim 15, further comprisinga communications microphone to detect speech to be conveyed to at aremotely located person through the PTT function of one of the radio andthe ICS of which the PTT function is engaged through operation of thePTT switch.
 19. The apparatus of claim 15, wherein the apparatuscomprises a headset having at least one acoustic driver structured to bepositioned adjacent at least one ear of a user of the apparatus at atime when the apparatus is worn on the user's head to acousticallyoutput audio provided by at least one of the radio and the ICS.
 20. Theapparatus of claim 19, wherein the PTT switch is disposed on a casing ofthe headset in which the acoustic driver is disposed.